In Iceland, the Yule Lads are stirring. And like so much in this strange β€” and strangely beautiful β€” place, they are not what you expect.

Yes, the Yule Lads appear at Yuletide, all 13 of them, and yes, they do bring gifts, of sorts. But their parents are repulsive trolls, and there is nothing Santa Claus-ish about them. Except maybe their white beards.

I'll come back to them. Every time I start to talk about Iceland, in fact, I come back to the Yule Lads and their various unseen relatives.

I can't resist, even though I should be talking about the country's shimmering fjords, dramatic waterfalls, shooting geysers and roaring steam vents; its trim fishing villages, cutting-edge architecture, nice people and some of the cleanest air on the planet.

Iceland sits just south of the Arctic Circle, but at a different latitude it could have been like Hawaii: an otherworldly volcanic creation of jagged, jet-black lava rock, anchored in a distant sea, thinly veiled by greenery, and populated, it is said, by more beings than meet the eye.

In both places, the geology is so exotic that believing in otherworldly creatures makes sense. In Hawaii, they are known as Menehune β€” little people, rather like leprechauns. In Iceland, however, the list of hidden life forms is longer than that. Quite a bit longer.

Even the national airline acknowledges this. The first thing I noticed after boarding an IcelandΒ­air flight from Minneapolis to Reykjavik this fall was a tourism commercial playing on seat-back TV screens. It was flashing facts about Iceland, of which this was my favorite: "The most interesting thing about Iceland isn't that more than 30 percent of the people have college degrees. It's that more than 50 percent of the people believe in elves."

Tongue-in-cheek, maybe, but not quite a joke.

Icelanders are well-educated and well- read β€” more books are published per capita there than anywhere else in the world β€” a fact that makes the persistence of elfish beliefs even more endearing.

I met only one Icelander who admitted that he believed in elves, but I never met anyone who flat-out said he didn't. Just in case. "An elf," a guide explained, "is generally not in a good mood."

Was it true, then, that Iceland doesn't build factories or new roads in certain areas because elves live there?

Well, people said, some companies do use, um, consultants β€” negotiators β€” experts who can politely urge elves to resettle elsewhere. Otherwise things might go wrong. Vehicles won't start. Construction equipment breaks down.

Viking past links Icelanders

The idea of this invisible population enchanted me, and for the rest of my stay, I asked Icelanders about it. So did my companions on a tour of the country's north and east.

The group, in fact, asked lots of questions, some naively American. These were typically followed by Icelandic pauses, while our various guides pondered how to respond.

An early example came during a discussion of energy conservation. "What about passive solar?" someone asked, thinking of Iceland's location, so far north that daylight lasts almost around the clock in summer.

An Icelandic pause. The questioner had overlooked summer's flip side, so our guide was looking for a nice way to bring up winter, when nights run more than 20 hours long in December and January. "Two months of the year," he finally said, "it would be very passive indeed."

Also unnecessary: More than 99 percent of Iceland's homes are heated with geothermal energy, thanks to its unique geology.

Iceland straddles the rift where the North American tectonic plate and the Eurasian plate are very slowly pulling apart, resulting in volcanic eruptions, frequent earthquakes, geysers, steam vents, hot pools and low heating bills.

"You just sink a hole," another guide explained, "and you get hot water."

Icelandic names were another puzzle. "How do you keep each other straight?" someone wondered, given that Icelanders are on a first-name basis with everybody, including the mayor of Reykjavik and the prime minister.

Last names, as we know them, are more like modifiers here β€” just your father's first name plus "-son" or "-dottir." Even the phone book lists people first-names-first.

This time, the Icelandic pause was brief. If you're looking for someone, we were told, and the phone book lists lots of people with the same name, you just call a few. One of your calls will either reach the person you want or someone who knows how to find him or her.

There's some truth in that, given the small size of the national population: fewer than 330,000 people, about two-thirds of whom live in or around the capital, Reykjavik.

More truth resides in the "Islendingabok," or "The Book of the Icelanders," which lists virtually all Icelandic families, down through history, including when and whence they arrived, where they settled and who their descendants are. It's a national genealogy, linking people to their collective Viking past. So in a way, Icelanders really do all know each other.

Further reminders of that shared history are the Viking artifacts that can still turn up when farmers plow their fields.

"Aren't you afraid of disturbing ancient burial grounds?" another in our group asked, clearly thinking of American Indian sites and the laws that protect them back home.

An especially long Icelandic pause followed that one.

"There are no ancient burial grounds," our guide said finally. Nobody was living in Iceland when the first permanent Viking settlers arrived in 874 A.D. So Iceland's native peoples are the modern Icelanders themselves.

Elves go underground

You can read accounts of Iceland's early years in its ancient sagas, complex oral histories that weren't written down until after the year 1000, when Iceland converted to Christianity.

They're regarded as Europe's first novels, or at least its first soap operas: lots of fighting, intrigue and drama. And lots of names. Several hundred sagas have been preserved, and nearly all begin with a long genealogy of the main figures: "There was a man named …" And there really was.

Iceland's chieftains agreed to Christianity at the annual meeting of Iceland's parliament β€” the first parliament in Europe, by the way β€” but with some reservations.

The king decreed that people didn't have to give up their old religion, they just couldn't practice it in public anymore. The result was a dual belief system β€” Christianity on the official surface, pagan beliefs lingering in private.

In effect, this drove the elves and their kinfolk underground, where some tended to be already, living in formations of rock.

That's true even for the Hidden People, the category that looks just like us β€” same size, same human features, just paler, maybe a little blue-ish. "You could walk right by them," I was told, "and you wouldn't know."

Yule Lads turn to gift-giving

Mid-trip, near Lake Myvatn, we came to an especially weird landscape of lava towers. Called Dimmuborgir β€” "dark castles" in English β€” it looks so much like a rock village that it couldn't help but attract unusual residents.

And in the way birdhouses tend to attract birds, it has. Dimmuborgir is the home of the Yule Lads.

The 13 Yule Lads are brothers, the sons of particularly nasty troll parents. Traditionally, the Lads were ugly, unpleasant creatures who threatened children and stole food, which explains most of their names: Spoon-licker, Pot-scraper, Bowl-licker, Yogurt-lover, Sausage-swiper, Meat-hook, Sniffer (he sniffs for holiday bread), Gully Gawk (hides in gullies, waiting to steal cow's milk), Gimpy (causes havoc by letting sheep out of their pens), Stubby (he's very short and likes leftovers), Door Slammer (he startles people, perhaps away from their food), Window Peeper (he looks for things to steal, especially food), and my personal favorite, Candle Stealer.

One tradition says that he stole candles because he loved light, especially in midwinter, but he was too poor to afford them. Given the starring role of food in this folk tale, however, it could also be because candles in olden times were made of animal fat and therefore also food.

The Yule Lads' legend has altered in the past century, apparently softened by benign competition from Santa Claus. Now they are regarded as pranksters who appear in the two weeks before Christmas, each on a different night, to dole out small gifts to good children and potatoes to naughty ones.

"I received many potatoes," one guide told us, sounding sad. Fortunately, he added, Santa now brings presents to everyone.

My last night in Akureyri, Iceland's second-largest city, population 18,000, a casual question of mine led to a more unsettling conversation.

"Are you from here?" I had asked my 40-ish guide, a genial black-bearded man named Gisli.

He gave me a long patient look. "My family has been here," he said gently, "for nearly twelve hundred years."

Wow, I said, from settlement times?

Yes, and a branch of his family still owns the original farm. We continued chatting and eventually got around to the Hidden People.

"They are real," Gisli said firmly. "Absolutely real."

How did he know?

"I have seen them," he said. "I saw a farmer leading two horses, and they all disappeared into a rock!"

Surely that was a fantasy remembered from childhood?

No, Gisli insisted. "It was last year!"

Now, back home in Minnesota, where winter is about as cold as it is in Iceland but not as haunted, I'm still enthralled by Iceland's invisible citizenry. I still talk more about them than about the country's music or its small sturdy horses. Or the ancient sagas. Or even all the outdoor thermal baths, heated by natural steam.

But I toned it down after a friend, who had listened with widening eyes, asked softly, "They wouldn't follow you, would they? I mean, they couldn't come … here?"

"No," I assured her, just in case she wasn't kidding, "they stay in Iceland." At least, I expect they do: The country's so remarkable, why would any of them want to leave?

Catherine Watson, former Travel editor at the Star Tribune, teaches travel and memoir writing. Her next workshop is at Madeline Island School of the Arts (www.madelineartschool.com) in August.